“pill” shaped. Relatively stationary. Not on radar?
How about a simple Mylar balloon?
If it’s not on primary radar, that means it doesn’t have a transponder.
Dollar store variety?
"There were no warps or creases on the surface, nor was it tapered at the bottom,' Hansen wrote."
Reminds me...
I found one of these in the far back of my property a couple of years ago. I'll have to look up the date. I didn't suspect that it was an alien -- plus it arrived with a lot of creases. Must have been a rough ride. I saved it of course. Its code no. is 523.

Then it must be a craft of some kind that does not have a transponder.
Learn the difference between primary and secondary radar..